Maximum Input Voltage

The Maximum Input Voltage setting determines the highest voltage the controller will allow before triggering an overvoltage fault.

A common starting point is approximately:

10-15% above the battery’s fully charged voltage

This provides some headroom for regenerative braking, which can temporarily increase battery voltage during operation.

⚠️ The Maximum Input Voltage must never exceed the maximum rated input voltage of the controller.

Exceeding the controller’s voltage rating can permanently damage MOSFETs, capacitors and other components, even if fault protection is configured correctly.

⚠️ Always refer to the controller datasheet when selecting voltage limits.

Example:
For a controller with an absolute maximum input voltage of 100V, the recommended maximum battery voltage is 92.4V, which corresponds to a fully charged 22S lithium-ion battery (22 × 4.20V = 92.4V).

The difference between the battery’s maximum voltage and the controller’s absolute voltage limit provides a safety margin for voltage spikes and regenerative braking events.

In VESC Tool, the Maximum Input Voltage should typically be set slightly below the controller’s absolute voltage limit. For a controller with a 100V absolute maximum input voltage, a setting of 98V is commonly used to provide an additional layer of protection against overvoltage conditions while maintaining the maximum available operating range.